Footwear midsole comprising an internal bladder

ABSTRACT

The presently disclosed subject matter is directed to a footwear midsole configured as an air-filled bladder formed from one or more exterior walls. The interior of the midsole comprises one or more fluids (e.g., gases or liquids). The midsole further includes a covering that partially or fully covers the interior compartment. The covering is formed form an elastomeric material that allows exclusive top-down compression of the midsole. Accordingly, the midsole provides a reactive opposed rebound force supplied by the elastomeric covering in response to compression.

TECHNICAL FIELD

The presently disclosed subject matter relates a midsole that can beused with a wide variety of footwear.

BACKGROUND

Athletic footwear generally includes a multilayer construction comprisedof an upper and a sole. The upper is designed to comfortably enclose atleast a portion of the wearer's foot, while the sole absorbs the harmfulimpact forces created during walking, running and the like. The sole canbe a single piece, but more commonly comprises an outsole, an insole,and a midsole therebetween. The outsole functions as a tough,wear-resistant layer with tread for providing traction against theground or floor. The insole is a thin, soft layer that provides comfortto the user's foot. The midsole is the primary structural layer in thesole and provides for shock absorption. The footwear midsole isgenerally constructed from a resilient foam material, such as ethylenevinyl acetate (EVA) or polyurethane, which provide cushioning andsupport to the wearer's foot. However, there are several drawbacksassociated with these materials. For example, over time, foam midsolesquickly become worn through compaction of the foam material. As aresult, the cushioning capacity of the shoe is greatly reduced,requiring the wearer to frequently replace the shoe. In addition, priorart midsoles comprising foam materials commonly store the energy fromthe foot strike while under compression, which can be immediatelyreturned (referred to as energy return or rebound). It has been shownthat foam rebound can produce undesirable shock to the wearer, leadingto injury. It would therefore be beneficial to provide a midsole capableof shock absorption and improved performance while maintaining thestructural integrity of the footwear.

SUMMARY

In some embodiments, the presently disclosed subject matter is directedto a footwear midsole comprising an interior compartment comprising afluid and an elastomeric covering spanning at least a portion of anexterior surface of the interior. The midsole enables top-downcompression when a force is exerted upon the midsole.

In some embodiments, the midsole further comprises an inflation housingthat allows fluid to be added or removed from the interior compartment.

In some embodiments, the fluid comprises a gas, a liquid, orcombinations thereof.

In some embodiments, the fluid is selected from ambient air, nitrogen,carbon dioxide, helium, or combinations thereof.

In some embodiments, the fluid is selected from water, saline, orcombinations thereof.

In some embodiments, the elastomeric material is selected from naturalor synthetic rubber, natural or synthetic rubber blends, polyisoprene,polybutadiene, chloroprene rubber, butyl rubber, styrene-butadienerubber, nitrile rubber, silicone, polyether block amides, ethylene-vinylacetate, thermoplastic elastomers, polyurethane, polyester, polyesterpolyurethane, polyether polyurethane, or combinations thereof.

In some embodiments, the interior compartment has a volume of about40-200 cubic centimeters.

In some embodiments, the covering is releasably attached to the midsole.

In some embodiments, the covering is attached to a top surface of themidsole.

In some embodiments, the covering creates an air-tight seal around themidsole interior compartment.

In some embodiments, the interior compartment includes two or moresub-compartments.

In some embodiments, at least one sub-compartment is in fluidcommunication with at least one other sub-compartment.

In some embodiments, the interior compartment is filled to about 40-100percent capacity.

In some embodiments, the fluid within the midsole interior has apressure of about 0-350 kPa.

In some embodiments, the presently disclosed subject matter is directedto an article of footwear. The article comprises a sole and an upper,wherein the sole comprises a midsole defined by an interior compartmentcomprising a fluid and an elastomeric covering spanning at least aportion of an exterior surface of the interior. The midsole enablestop-down compression when a force is exerted upon the midsole.

In some embodiments, the sole further comprises an insole and anoutsole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a side plan view of footwear comprising a midsole inaccordance with some embodiments of the presently disclosed subjectmatter.

FIG. 1b is a side plan view of a footwear sole in accordance with someembodiments of the presently disclosed subject matter.

FIG. 2a is a side plan view of a midsole in accordance with someembodiments of the presently disclosed subject matter.

FIG. 2b is a side plan view of a midsole in accordance with someembodiments of the presently disclosed subject matter.

FIG. 3 is a fragmentary view of a midsole inflation housing inaccordance with some embodiments of the presently disclosed subjectmatter.

FIGS. 4a-4g are top plan views of midsoles comprising one or morecompartments in accordance with some embodiments of the presentlydisclosed subject matter.

FIGS. 5a-5d are side plan views of one embodiment of using the disclosedmidsole.

DETAILED DESCRIPTION

The presently disclosed subject matter is introduced with sufficientdetails to provide an understanding of one or more particularembodiments of broader inventive subject matters. The descriptionsexpound upon and exemplify features of those embodiments withoutlimiting the inventive subject matters to the explicitly describedembodiments and features. Considerations in view of these descriptionswill likely give rise to additional and similar embodiments and featureswithout departing from the scope of the presently disclosed subjectmatter.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which the presently disclosed subject matter pertains.Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of thepresently disclosed subject matter, representative methods, devices, andmaterials are now described.

Following long-standing patent law convention, the terms “a”, “an”, and“the” refer to “one or more” when used in the subject specification,including the claims. Thus, for example, reference to “a device” caninclude a plurality of such devices, and so forth.

Unless otherwise indicated, all numbers expressing quantities ofcomponents, conditions, and so forth used in the specification andclaims are to be understood as being modified in all instances by theterm “about”. Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the instant specification and attachedclaims are approximations that can vary depending upon the desiredproperties sought to be obtained by the presently disclosed subjectmatter.

As used herein, the term “about”, when referring to a value or to anamount of mass, weight, time, volume, concentration, and/or percentagecan encompass variations of, in some embodiments +/−20%, in someembodiments +/−10%, in some embodiments +/−5%, in some embodiments+/−1%, in some embodiments +/−0.5%, and in some embodiments +/−0.1%,from the specified amount, as such variations are appropriate in thedisclosed packages and methods.

FIG. 1a illustrates one embodiment of footwear 5 configured as anathletic shoe that includes a midsole structure in accordance with thepresently disclosed subject matter. The midsole can be configured foruse with various kinds of footwear, such as hiking boots, soccer shoes,football shoes, running shoes, cross-training shoes, rugby shoes,basketball shoes, baseball shoes, and the like. It should be appreciatedthat the footwear can also include non-athletic shoes, such as slippers,sandals, high heeled shoes, loafers, etc. Thus, the term “footwear”broadly refers to any foot covering, including (but not limited to)athletic shoes, boots, sandals, and the like.

For reference purposes, footwear 5 can be divided into three generalregions: forefoot region 30, midfoot region 31, and heel region 32, asshown in FIG. 1a . Forefoot region 30 generally includes portions offootwear 5 corresponding with the toes and the joints connecting themetatarsals with the phalanges. Midfoot region 31 generally includesportions of the footwear corresponding with the arch area of the foot,and heel region 32 corresponds with rear portions of the foot, includingthe calcaneus bone. It should be appreciated that regions 30-32 are notintended to demarcate precise areas of footwear 5. Rather, the regionsare intended to represent general areas of the footwear.

As shown, footwear 5 includes upper 10 designed to securely enclose atleast a portion of the wearer's foot. Upper 10 can have any of a widevariety of configurations incorporating a range of conventionalmaterials, such as (but not limited to) textiles, foam, leather, vinyl,nylon, and the like. The material elements can be selected andpositioned in upper 10 to selectively impart one or more desiredproperties (e.g., durability, air-permeability, wear-resistance,flexibility, comfort, and the like). The materials are stitched oradhesively bonded together to form interior void 20 for securely andcomfortably receiving at least a portion of the wearer's foot. In someembodiments, upper 10 can include closure 25 configured as a shoelace,zipper, snap, button, VELCRO®, etc. that is utilized to secure thewearer's foot within the interior void of the footwear. The closure alsofacilitates entry and removal of the foot from the footwear. In someembodiments, the closure can extend through apertures in upper 10, and atongue portion can extend between the interior void and the closure.

It should be appreciated that upper 10 can have any design, shape, sizeand/or color. For example, in embodiments wherein the footwear is abasketball shoe, the upper can be configured as a high top that isshaped to provide added support on the wearer's ankle. Alternatively,when footwear 5 is a running shoe, upper 10 can be configured with a lowprofile.

In addition to upper 10, footwear 5 comprises sole 15 that functions toabsorb the impact forces on the wearer's foot during use. In someembodiments, the sole can extend generally the entire length of thefootwear from toe region 16 to the heel portion 17, as shown in FIG. 1a. The sole is secured to a lower face of upper 10 using any knownmethod, such as (but not limited to) the use of adhesive, sewing,thermal bonding, mechanical elements, and the like. The sole ispositioned between upper 10 and the ground, thereby extending betweenthe foot and the ground. In this way, the sole can provide traction,impart stability, and limit various foot motions (such as pronation).

FIG. 1b illustrates one embodiment of sole 15. As illustrated, theprimary elements of sole 15 include insole 35, midsole 40 and outsole45. In some cases, one or more of these components can be optional.Insole 35 is positioned within the interior void in upper 20 and islocated to correspond with a plantar (i.e., lower) surface of the foot,thereby enhancing the comfort of footwear 10. Midsole 40 is secured to alower surface of the insole and attenuates ground reaction forces assole 15 is compressed between the foot and the ground, such as duringwalking or running. Midsole 40 may also absorb energy when compressed.Midsole 40 includes a sealed fluid-filled chamber, which will bediscussed in detail below. The outsole is the outer surface of thefootwear that contacts the ground. Outsole 45 is secured to a lowersurface of the midsole and is formed from a durable andabrasion-resistant material (such as rubber) that can be textured todefine various protrusions for providing traction.

One embodiment of midsole 40 is depicted in FIG. 2a . As shown, themidsole can include provisions for shock absorption, cushioning, andcomfort. Particularly, the midsole can be configured as an air-filledbladder formed from one or more exterior walls 50. The exterior wallscan include any suitable material used to contain a fluid-filledinterior. For example, suitable materials can include (but are notlimited to) polymeric material, rubber, elastomeric material, and thelike. Interior 51 is filled with any desirable fluid. The term “fluid”as used herein refers to any suitable liquid, gas, or combinationthereof. Suitable gases can include (but are not limited to) one or moreof ambient air, nitrogen, helium, carbon dioxide, etc. Suitable liquidscan include (but are not limited to) water, saline, or combinationsthereof. The exterior walls of the midsole are sealed to contain thefluid.

The interior of midsole 40 can house any desired volume of fluid. Forexample, the midsole can have an interior volume of about 40-200 cc(cubic centimeters). Thus, the internal volume of the midsole can be atleast/no more than about 40, 50, 60, 70, 80, 90, 100, 110, 120, 130,140, 150, 160, 170, 180, 190, or 200 cc. It should be appreciated thatthe volume of the midsole depends on the size of the midsole (e.g., thesize of the user's foot). It should further be appreciated that themidsole can have a volume greater or less than the range given herein.

Midsole 40 can have a thickness 41 of about 0.1-3 inches, as shown inFIG. 2a . The term “thickness” as used herein refers to the measurementof an insole from its top surface to its opposing bottom surface. Themidsole can have a thickness at rest of at least about (or no more thanabout) 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3,1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8,2.9, or 3 inches. “At rest” refers to the thickness without contact withthe wearer's food (e.g., an uncompressed state). It should beappreciated that the midsole thickness is not limited and can be greateror less than the range given herein.

In some embodiments, the midsole is configured to be about the entirelength of the footwear, as shown in FIG. 2a . Thus, the midsole can havelength 42 of about 5-16 inches, depending on the size of the wearer'sfoot (e.g., at least/no more than about 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, or 16 inches). However, the length of the midsole is not limitedand can be greater or less than the range given herein.

The midsole is at least partially enclosed by covering 55 as shown inFIGS. 2a and 2b . Specifically, the covering can be positioned on thetop surface or can surround all or a portion of the exterior surface ofthe midsole. The covering can be releasably or permanently attached tothe midsole to create an air-tight seal. Covering 55 can be attached tothe midsole using any known method, such as (but not limited to)adhesives, welding, heat sealing, etc.

Covering 55 can be constructed from any desired material. For example,in some embodiments, the covering can be constructed from one or moreelastomeric materials. The term “elastomeric” refers to a material thatcan be elongated or extended by at least 5, 10, 15, 20, or 25% of itsrelaxed length and that will recover upon release of the applied force.Suitable elastomeric materials can include (but are not limited to)natural or synthetic rubber, natural or synthetic rubber blends,polyisoprene, polybutadiene, chloroprene rubber, butyl rubber,styrene-butadiene rubber, nitrile rubber, silicone, polyether blockamides, ethylene-vinyl acetate, thermoplastic elastomers, polyurethane,polyester, polyester polyurethane, polyether polyurethane, orcombinations thereof.

The covering can have a thickness of about 0.001-100 mm. Thus, thecovering can have a thickness of at least about (or no more than about)0.001, 0.005, 0.01, 0.015, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08,0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3,3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 20, 30, 40, 50,60, 70, 80, 90, or 100 mm. However, it should be appreciated that thethickness of the covering is not limited and can be thicker or thinnerthan the range given herein.

Optionally, midsole 40 can include housing 60 that facilitates theinflation of the midsole. The housing can be disposed on any surface ofthe midsole to allow fluid to be selectively added or removed from themidsole interior by the user, as illustrated in FIG. 3. In operation, afluid (such as ambient air) passes through the housing into the interiorof midsole 40. The housing can therefore include a port, valve, plug,aperture, or combinations thereof. In some embodiments, the housing canbe a one-way or two-way valve. In some embodiments, the housing can beconfigured as a check valve that will open when the pressure within themidsole interior is at or greater than a predetermined level.

A variety of different inflation mechanisms can be utilized with housing60. For example, the inflation mechanism can include a simple bulb thatinteracts with the housing to add or remove fluid from the midsoleinterior. Alternatively, a pump (e.g., a handheld pump) can be used toinflate the midsole.

In some embodiments, the interior of the midsole can be filled to about100% with a desired fluid. In other embodiments, interior 51 is lessthan fully filled. For example, midsole can be filled to about 40-100%capacity. Thus, the midsole can be filled to a level of at least about(or no more than about) 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,99, or 100 percent. In some embodiments, the fluid within the midsoleinterior can be pressurized between 0-350 kPa (e.g., at least/no morethan about 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75,80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150,155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220,225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290,295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, or 350 kPa).

In some embodiments, the midsole can be divided into one or morecompartments 65. For example, as shown in FIGS. 4a-4c , the compartmentscan be configured in a longitudinal direction, crosswise direction, orcombinations thereof.

In some embodiments, the compartments span the full midsole, as shown inFIGS. 4a-4c . However, the presently disclosed subject matter alsoincludes embodiments wherein the compartments are limited to one or moresections of the insole (e.g., the forefoot region, midfoot region,and/or heel region), as illustrated in the embodiments of FIGS. 4d and 4e.

It should further be appreciated that the midsole can include a singlecompartment, as illustrated in FIG. 4f . As shown, compartment 65 canextend under substantially all of the wearer's foot.

In some embodiments, the compartments are separated from adjacentcompartments as shown in FIG. 4a . Alternatively, one or morecompartments may be in fluid communication with at least one othercompartment, as shown in FIG. 4g . In this way, the movement of airbetween compartments is permitted and can be controlled by the size ofopening 66.

The compartments can be inflated to the same or different pressuresdepending on the type and amount of cushioning needed.

The shape of compartments 65 is not limited and can be configured in anydesired shape and size, such as (but not limited to), square,rectangular, rounded, serpentine, abstract, and the like. The shapeand/or size of each compartment can be about the same or can differrelative to at least one other compartment.

It should be appreciated that midsole 40 can include any number ofcompartments 65, such as about 1-10. However, the presently disclosedsubject matter is not limited and the midsole can have more than 10compartments (e.g., 10-100 compartments).

The midsole can be manufactured using any known method. For example, twoseparate layers of material (e.g., elastomeric film) are formed to havethe overall shape of the midsole. The layers are then bonded togetheralong their respective peripheries to form an upper surface, a lowersurface, and sidewalls of the chamber. The layers can optionally bebonded together at predetermined interior locations to produce one ormore compartments 65. The midsole (or compartment(s) can optionally bepressurized by inserting a nozzle or needle, which is connected to afluid pressure source, into a fill inlet formed in the midsole. Afterthe midsole is pressurized, the nozzle is removed, and the fill inlet issealed. Covering 55 can be permanently or removably attached to at lastone portion of the exterior surface of the midsole using known methods(e.g., adhesives, thermal sealing, etc.). However, the presentlydisclosed subject matter is not limited and the midsole can be formedusing any known method.

Advantageously, midsole 40 provides improved shock absorption andrunning/leaping efficiency compared to prior art midsoles. As describedabove, a fluid (which can be air at atmospheric pressure) is trappedwithin the midsole interior. In some embodiments, the fluid can becontained in one or more compartments 65. In use, when a user isstanding in the footwear, the fluid in the midsole provides a cushioningeffect, as shown in FIG. 5a . However, when the wearer runs or steps,the midsole is compressed exclusively from the top-down. Particularly,the heel portion of the outsole first comes into contact with theground. As a result, the heel of the wearer's foot exerts a downwardpressure on midsole 40. The fluid within the midsole in the area of theheel pressure will then be compressed as shown by the arrow in FIG. 5b .In some embodiments, the compressed fluid will travel throughcompartments 65.

In response to the compression, the fluid positioned within the interiorof the midsole provides a reactive force upon release to give a liftingeffect, as the wearer's weight shifts to the front part of the foot. Thereactive force is performed by covering 55 due to the elastomeric natureof the material used, as shown by the arrows in FIGS. 5c and 5d . Thereactive force can be exerted on the user's foot (heel, middle, or ballpositions) in the form of a rebound force. Thus, in walking and running(and other movements), the fluid is compressed and then the coveringprovides the rebound force to give an alternating lifting effect andprovide thrust that facilitates walking and running. As a result, themidsole provides improved shock absorption and allows the wearer greatermobility when running, leaping, etc.

Although midsole 40 may be especially advantageous when used withathletic shoes, the presently disclosed subject matter is not limitedand the midsole can be used with any type of footwear.

The disclosed midsole therefore provides for a unique top-bottomcompression, enabled by elastomeric covering. As a result, the reactiveforce that occurs after compression provides a benefit to the wearer inthe form of a burst of compression release.

The disclosed midsole is simple to manufacture and can be easily usedwith existing footwear.

The presently disclosed subject matter is disclosed above and in theaccompanying drawings with reference to a variety of embodiments. Thepurpose served by the disclosure, however, is to provide an example ofthe various features and concepts related to the invention, not to limitthe scope of the invention. One skilled in the relevant art willrecognize that numerous variations and modifications can be made to theembodiments described above without departing from the scope of thepresent invention, as defined by the appended claims.

What is claimed is:
 1. A footwear midsole comprising: an interiorcompartment comprising a fluid; and an elastomeric covering spanning atleast a portion of an exterior surface of the interior; wherein themidsole enables top-down compression when a force is exerted upon themidsole.
 2. The midsole of claim 1, further comprising an inflationhousing that allows fluid to be added or removed from the interiorcompartment.
 3. The midsole of claim 1, wherein the fluid comprises agas, a liquid, or combinations thereof.
 4. The midsole of claim 1,wherein the fluid is selected from ambient air, nitrogen, carbondioxide, helium, or combinations thereof.
 5. The midsole of claim 1,wherein the fluid is selected from water, saline, or combinationsthereof.
 6. The midsole of claim 1, wherein the elastomeric material isselected from natural or synthetic rubber, natural or synthetic rubberblends, polyisoprene, polybutadiene, chloroprene rubber, butyl rubber,styrene-butadiene rubber, nitrile rubber, silicone, polyether blockamides, ethylene-vinyl acetate, thermoplastic elastomers, polyurethane,polyester, polyester polyurethane, polyether polyurethane, orcombinations thereof.
 7. The midsole of claim 1, wherein the interiorcompartment has a volume of about 40-200 cubic centimeters.
 8. Themidsole of claim 1, wherein the covering is releasably attached to themidsole.
 9. The midsole of claim 1, wherein the covering is attached toa top surface of the midsole.
 10. The midsole of claim 1, wherein thecovering creates an air-tight seal around the midsole interiorcompartment.
 11. The midsole of claim 1, wherein the interiorcompartment includes two or more sub-compartments.
 12. The midsole ofclaim 11, wherein at least one sub-compartment is in fluid communicationwith at least one other sub-compartment.
 13. The midsole of claim 1,wherein the interior compartment is filled to about 40-100 percentcapacity.
 14. The midsole of claim 1, wherein the fluid within themidsole interior has a pressure of about 0-350 kPa.
 15. An article offootwear comprising: a sole; and an upper; wherein the sole comprises amidsole defined by: an interior compartment comprising a fluid; and anelastomeric covering spanning at least a portion of an exterior surfaceof the interior; wherein the midsole enables top-down compression when aforce is exerted upon the midsole.
 16. The article of claim 15, whereinthe sole further comprises an insole and an outsole.
 17. The article ofclaim 15, wherein the elastomeric material is selected from natural orsynthetic rubber, natural or synthetic rubber blends, polyisoprene,polybutadiene, chloroprene rubber, butyl rubber, styrene-butadienerubber, nitrile rubber, silicone, polyether block amides, ethylene-vinylacetate, thermoplastic elastomers, polyurethane, polyester, polyesterpolyurethane, polyether polyurethane, or combinations thereof.
 18. Thearticle of claim 15, wherein the fluid comprises a gas, a liquid, orcombinations thereof.
 19. The article of claim 15, wherein the interiorcompartment includes two or more sub-compartments.
 20. The article ofclaim 15, wherein the fluid within the midsole interior has a pressureof about 0-350 kPa.